Is either some example code or a detailed written description available for the improved DRS4 timing-calibration algorithm described by Daniel Stricker-Shaver at MIC 2012? I think you told me that you had verified the results with your own test set-up, so I figure there must be at least two sets of code in existence to implement this calibration. (I have Daniel's presentation slides.)
I managed to find a ping-pong distribution of cell widths that looks quite similar to that shown in Daniel's slides, using an algorithm similar to the technique one uses to find radial offsets in a tracking chamber (i.e. using residuals weighted by track slope), but I'd rather use the method with which you and Daniel have already found good results. (The attached graph shows in black the histogram of cell widths for essentially the algorithm used in DRS.cpp/DRSBoard::AnalyzeWF, and in blue the histogram of cell widths extracted from the slope-weighted residuals for a periodic reference signal.)
By the way, since Daniel finds a FWHM coincidence-timing resolution around 20-25ps at 5 GSPS (for perfectly identical pulses), should I expect a FWHM resolution (for synthesized, ideal pulses) of around 50-65ps at 2 GSPS?
(I'm posting here instead of writing you both privately because I figure there may be broader interest in Daniel's algorithm.)